Today, various content filtering mechanisms are provided to entities to manage and/or control user access to the Internet via facilities provided by the entities. For example, a company typically implements some forms of content filtering mechanisms to control the use of the company's computers and/or servers to access the Internet. Access to content within certain predetermined categories using the company's computers and/or servers may not be allowed during some predetermined periods of time.
For example, a typical content filtering client, which typically resides within a firewall, sends a request for the content rating of a web page in response to each web page browsed. The content rating requests are routed to a separate content rating server. When the content rating server receives a request, the content rating server retrieves the content rating for that request from a database and sends the content rating to the content filtering client. Based on the content rating retrieved, the content filtering client determines whether the user is allowed to access the web page. If the user is allowed, the content filtering client passes the web page. Otherwise, the content filtering client blocks the web page.
As the amount and type of multimedia content on the Web keep growing, the ability to access a large amount of multimedia content from the Web raises new questions on how to classify or rate such content, in order to provide content security. Although conventional content filtering techniques work well on text-based content, such techniques are not able or work poorly to perform content filtering on multimedia content, such as, for example, audio and/or video content.